Is there a specific question you're asking? Or are you just curious with how often people use 3-key lighting for photos and video?
Its a thread on video techniques, so share some.
I mean, you're into media production... anything you want to share?
For example, as I said earlier, video techniques are similar to photography. Rule of thirds works on video too. But cropping isn't always something you want to do with video, so you need to frame it that way before taking the video.
You may want to move the camera a certain way to add interest to the scene. Look into sliders, jibs/cranes and stabilizers.
I agree with above, I'd be surprised if you were using 3-point lighting 5% of the time! Most of the time you have two options: use natural light, or use incredibly complex lighting setups to imitate natural light! Of course you'll want to use reflectors, diffusers and fill lights when necessary to stretch what natural light gives you, but most of the time "natural light" is fine. Quotes because I count amped natural light into natural light (brighter burning candles, higher output light bulbs that look like lower output lightbulbs, the usual). Remember, all light is available light, and all light follows the same rules! Different light sources give different initial light, but how your subject is lit depends on the interaction between your lightsource and the subject. In lighting there are three active parties: the light, the gobos, and the subject. Each will have their own effect on the light and the final light you see is a sum of those three factors.
Two biggest mistakes you can make in video: exposure all over the place and bad audio. Audio is 50% of video. No matter how amazing your video is, it will seem horrible if the audio is bad. Never change exposure during a scene. Over/underexposure is better than your camera changing exposure moving from window to your subject or anything like that. 100% of the time. No exceptions. Of course if you go INT -> EXT or vice versa you use different exposures for the INT and the EXT, but never change the exposure during a scene. If you film the subject opening a door, the exposure doesn't change within the scene! If it looks bad shot from INT->EXT, change to EXT and use EXT exposure, shooting the door from the outside! Just don't change the exposure during a scene, ever.
Framing "rules" are the same for paintings, photography and video. Aesthetically pleasing is just that regardless of media. If you have the eye for it, it's obvious, you will immediately know if your composition and framing works or not.
You got one point right: the end result won't be exactly what you thought in the beginning, but when you get to the end, you wouldn't want it to be! Unless talking about clockwork like video production where every position of every light and every object is dictated by the client to the last millimeter, your vision and the end result will evolve during production, it's a pretty organic progression.
After exposure, composition and audio, the biggest thing is stability. Unless you're doing a Sam Raimi type scene in the forest, you'll need stabilizers, and they should not be wooden planks either. Tripod for static scenes where the camera doesn't have to move other than pan or tilt, a crane for crane shots (though you can improvise a crane too! Here you can use wooden planks! Just remember to use a tripod head too.) A vehicle mount for side of the vehicle shots (also easy to DIY, really, if you make it stable and use the correct materials and it makes no difference. Paint it black if it offends your aesthetic sensibilities. Again, use a tripod head, and not a cheap one.) Some things you're better off just buying, DO NOT DIY: gliders, steadycam rigs, shoulder mounts, arm support, vests, matte boxes, and so on. Just buy them, and don't buy the cheap stuff either, otherwise you'll buy twice. Just save yourself the trouble. If you absolutely can't afford a steadicam and you absolutely need steady moving shots, get the "DSLR" dubbed version of flycam. It's usable, unlike most of the cheap copies.